I use to use a CA water blade, but have lately noticed some small hair line scratches that I think were caused by it, so it's temporarily retired. I've got 2 black BMWs and work VERY hard to keep them perfect. Mine is driven 25k a year and is a '98, but you would never know. i learned everything that I know about pampering paint on http://www.autopia-carcare.com/ A ton of good info and some real fanatics. Here's a shot of my daily driver.

I used the water blade once and noticed long horizontal scratches on the hood, roof, and trunk. Just like swirl marks, they are more noticeable depending on the lighting. I'm never using the blade again.